Thermostatic control



June 4, 1929. w, w, MCLAREN 1,715,464

.THERMOS'IATIC CONTROL Filed May 1927 2 Sheets-Sheet 1 June 4, 1929. w, w, McLAREN 1,715.464

THERMOSTATI C CONTROL Filed May 1927 {Sheets-Sheet 2 gwomoo WMLam/a Patented June 4, 1929.

UNITED STATES WILLIAM W.'MCLARE N, F BIRMINGHAM, ALABAMA.

THERMOSI'ATIC common.

Application filed Kay 9, 1927. Serial No. 190,004.

The'device forming the subject matter of this application is an electric switch adapted to be used for various purposes, but, more especially, in connection with fiat-irons. The

switch acts thermostatically, and the primary.

object of the invention is to provide a quickacting thermostatic switch which will not get out of order readily.

It is within the province of the disclosure to improve generally and to enhance the utility of devices of that type to which the invention appertains.

\Vith the above and other objects in view which will appear as the description proceeds, l5

arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the drawings,:-

Figure 1 shows in elevation, a device con structed in accordance with the invention, parts being in section;

Figure 2'is a top plan of the structure shown in Figure 1, parts being omitted;

Figure 3 is a section on the line 33 of Figure 1;

Figure 4 is a section on the line 4-4 of Figure 1;

Figure 5 is a section on the line 55 of Figure 1;

Figure 6 is an elevation showing a modification Figure 7 is an elevation showing another modification.

Referring especially to the form shown in Figures 1 to 5, the numeral 1 marks a circuit, one conductor 2 of which is joined to bifurcated resilient switch terminals 3 carried by a bar 4 forming part of a support 5. The terminals 3 are adapted to be engaged by a bridge, to close the circuit, and the bridge may be a' Wing 6 on a tubular body 7 held by a set screw 8 on an insulating sleeve 9 carried by an arm 10 having a foot 11 secured to a bowed spring 12 at a point intermediate the ends of the spring. As shown in Figure 2, at 15, the spring 12 is reduced in width toward its ends, but as shown at 14 in Figure 1, the spring tapers in thickness from its ends toward its intermediate portion. The spring 12 is supplied at its ends with eyes 16 mountthe invention resides in the combination and.

ed loosely on projections 17 which extend from a support 18. At one end, the spring 12 is supplied with a projecting finger 19.

The thermostatic means for operating the switch may be of various kinds. Thus, in F igures 1 and 5, there is shown a bracket 20 having a base 21 to which a bar 22 is secured at 27, the coeflicient of expansion of the bar 22 being different from that of the bracket 20, the bar 22 having an elongated slot 23 receivin a securing element 24 which is mounted in the bracket 20, the upper end of the expansion bar 22 hearing on a tongue 25, one end of the tongue being secured at 26 to the upper end of the bracket 20, and the other end of the tongue being received in the bifurcated linger 19 on the spring 12.

In practical operation, when the bar 22 expands, the tongue 25 is flexed upwardly, the spring'12 snapping from the solid line position of Figure 1 to the dotted line position of that figure, the bridge or wing 6 being moved out of contact with the switch terminals 3 and the circuit being opened accordingly.

In Figure 6 of the drawings, parts herein before described have been designated by numerals previously used, with the sutfix a.

In this form of the invention, the finger 19 is connected to a spring 28 which is united with one of the concaved walls of a metallic receptacle 29 in which is located a liquid 30 which will expand and contract with temperature changes. The description of the device Y shown in Figure 6, so far as operation is concerned, will be understood readily from what has been stated hereinbefore in connection with the form depicted in Figure 1 of the drawings.

In Figure 7, the bowed spring is shown at 31 and is provided at one end with an eye 32 mounted to turn on a fixed pin 33 or other projection, the spring 31 being supported intermediate its ends. between fixed guides 34. One end of the spring 31 is pivoted at 35 to the curved arm 36 of a Bourdon tube 37 including an annular body 38, liquid 39 being mounted in the tube 37, and adjustment being effected through the instrumentality of a screw 40 threaded into the body and entering the liquid 39.

The conducting bridge is shown at 41 and is carried by the spring 31, the bridge 41 being insulated from the'spring 31 as shown at 42. The arms 43 of the bridge are adapted to cooperate with resilient bifurcated switch terminals 44 mounted on an insulating support 45, the conductors 46 being connected to the terminals 44.

The tube 37 will respond to temperature changes and flex the spring 31 to move the bridge 41 out of engagement with the terminals 44.

What is claimed is 3 1. In a device of the class described, a bowed spring having openings, one opening being in one end of the spring, and the other opening being located intermediate the ends of the spring and near to the opposite end of the spring, a thermostat connected to the lastspecified end of the spring, a switch member carried by the spring and located between the openings, and supports engaged in the openings, the spring being tapered from the openings to the intermediate portion of the spring, thereby to enhance the resiliency of the spring and to leave at the ends of the spring, an increased amount of material, in which the openings may be formed advantageously.

2. In 'a device of the class described, a bowed spring, means for supporting the spring at spaced points, a thermostat connected to one end of the spring, an arm secured to the spring and disposed at an acute angle to the spring, an insulating sleeve in which the arm is received, a tubular body receiving the sleeve and having a projecting wing, a switch terminal wherewith the wing cooperates, and means for holding the body on the sleeve for circumferential adjustment, so that the Wing may be placed to cooperate with the switch member when the spring is flexed in one direction.

In testimony that I claim the foregoing as my own, I have hereto aflixed my signature.

WILLIAM W. MCLAREN. 

